Pump or motor unit



Aug. 7, 1945.

C. E. GROSSER PUMP OR MOTOR UNIT 3 Sheets-Sheet 1 Filed Oct. 22, .1942

m k, M r W a b w T M .i-iI m H MM. W NN NN- A w .a 2 mm Tu w S 8 3V g a m m w 5 Sheets-She et 2 CZ E. GROSSER PUMP OR MOTOR UNIT Filed Oct. 22, 1942 Aug. 7, 1945.

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Aug. 7, 1945.' C. E. GROSSER 2,381,741

PUMP OR MOTOR UNI-T Filed 001:. 22, 1942 3 sheets-Sheet 3 trimaxes-i.

Patented Aug. 7, 1945 UNI-TED- stares PATENT mm Christian E. Grosser, .Winchester, Mass, assignmto' Standard Machinery Company; Cranston; R. I., a corporation of Rhode Island ApplicatiomOctobenZZ, 1942, Serial N0."462,939 18 Claims. (Cl; 103-161) The; present invention relates to hydraulic variable-speed powerstransmission apparatus and more particularly to: improvements in the pump and motor units-of such apparatus.

One'ofthe objects ofthe present invention is tons andhavingarcuate rocker-bearings at their opposite end'concentric with their. pivotal connection'to the-pistons and engageable with thering tangentially. i i

.Another'object: is to provide a motor or pump unit of the type indicatedin' whichthe contact faces oithe reaction: ring; and. thewcontactfaces of the rocker-bearings I of; the piston-rods. are so formed asrto =cause' their. points of tangential en'- gagement'tozalinewith the: axes of their respective:cylinders in anyangular position of the -pis--- ton.-rcds.

Another; object-is?- to provideg novel form: of coupling for: connecting; the:- cylindezr-block and reaction ringfor'rotation i as ay unit about: eccen- Anotlier objectisto providea 'oouplingiof the typeindicated; having'radial arms which connect the: eccentric members fonrotation: and which rock: on" a fixedipivot for? anyvparticular' adjustment of.the eccentricity? Another objectuis to; provide a radiali pump! or motoruniti or the typeindicated with-cooperating ported; valvememhersz-on thercylindevblock; and enclosinglrcasing for" controlling: the" intake. and

Another object is to provide a pump or motor unit. of: the type: indicated with means operated by the motive fluidior applying. a: predetermined axial-.2 thrust to the cylinder-blockto hold the valve+members in engagement Anothersobjiect. is to provide-ahydraulic power. transmission: apparatus" having. pump" and; motor units. in: the' same casing: cooperating: with. th opposite.sidesof-asingle valves-annulus;

Still another object. is? to provideanz: apparatus of the type indicated which is of simple and compactconstruction, eflicient in performing its intended. functions and'adaptedfor use. over. long periodsof time Without requiring repair or; replacement of its parts.

Further objects of the invention are set forth in the following: specification which describes several forms of construction of the apparatus, by way ofrexample, as illustrated by the accompanyingdrawings. In the drawings:

Fig.- 1v is apart-sectional elevational view of. a hydraulic variable-speed power-transmission apparatus having pump and motor units incorporating=the novel featuresofzthe present invention;

Fig. 2. isa-part-sectional view on.line.,2-2 of Fig. 1; or on'a corresponding line through the pump, showing the'curved rocken-bearingsat the ends of-the piston-rods in tangential engagement with the flatfaces-on the reaction ring and illustrating the various angular positions of the pistonerods; Fig. 3 is-a-view similar to Fig. 2 showinga modified form=oi construction of the. reactionring as having. a cylindrical interiorsurface for tangential engagement bytherocker-bearings at the endsof the piston-rods Fig. 4 is a transverse sectional View taken generally on line 44- of .Fig. 1. showing the coupling for connectingthe motor shaftand reaction ring for rotation about eccentric axes;

Fig. 5 is a diagrammatic view illustrating the automatic adjustment of. the center of the coupling resulting from manual adjustment ofthe eccentricity of the reactionring with respect: to the shaft;

Fig. 6 is a transverse sectional View on line 6-6 of Fig. 1- showing the ported valve-plate on the casing and illustrating the relative positions of the cooperating ports in the cylinder-block; and

Fig. 7 is anenlar'ged sectional View on line 'l'! of Fig. 1 showing the ball-and-socket connection ofthe piston-rod. to its piston.

The pumps and motors commonly used in hydraulic variable-speed: power-transmission appa ratus comprise radial cylinders arranged inangular spaced relationship for-rotation about a fixed axis and a, reaction ring surrounding the cylinders .withits axis eccentric to the axis of rotation of the cylinders. Pistons are provided in. the cylinders and piston-rods extend between the pistons and the reaction. ring. The cylinderblock and ring are rotated as a unit and due to the eccentricity of their axes the ring moves relatively ofthe cylinder-block during rotation through the same angular distance. Usually,

shoes are provided at the ends of the piston-rods which bear against the ring and slide thereon. With such a form of construction the shoes are subject to excessive wear and considerable energy is dissipated in the friction resulting from the sliding action of the shoes on the ring. It is preferable to positively couple the cylinder-block and reaction ring for rotation as a unit, but the usual types of couplings for connecting the members for rotation about eccentric axes have reciprocating parts which produce vibration, especially where heavy loads are transmitted at high speed. Furthermore, the cylinder-blocks of such radial pump or motor units are usually mounted to rotate on ported pintles which control the intake and exhaust of motive fluid to and from the cylinders. With motive fluid at pressures of the order of twelve-hundred pounds per square inch leakage is caused between the block and ported pintle, especially after the contacting parts become worn.

The present invention relates generally to radial pump or motor units for use in hydraulic variable speed power transmission apparatus having the usual radial cylinders and reaction ring, but provided with piston-rods adapted to rock on the ring to materially reduce friction and wear. For this purpose, each piston-rod is pivotally connected at one end to its piston and has a rigid rocker-bearing at its opposite end provided with a curved periphery engageable with the interior of the reaction ring tangentially thereof. During rotation of the cylinder-block and reaction ring about eccentric axes the curved peripheries of the rocker-bearings at the ends of the piston-rods will rock on the ring to compensate for the relative movement therebetween. The contacting surfaces of the rocker-bearings and the reaction ring may have any particular contour to give a piston-stroke of the desired characteristics, but preferably the ring is pro vided with fiat faces arranged equidistant from its axis with one face opposite each cylinder and the periphery of the rocker-bearing of each piston-rod is curved to an arc concentric with its pivotal connection to the piston. With such an arrangement of contactingsurfaces on the pis; ton-rod and ring the line of tangential engagement is always alined with the axis of the cylinder in any angular position of the piston-rod.

The cylinder-block and reaction ring of the pump or motor unit are connected for rotation at the same angular velocity by means of acoupling comprising radial arms pivotally connected at their inner ends and having articulate sliding connections with the cylinder-block and ring. The arms of such a coupling will rotate about their pivotal connection as an axis and' swing with respect to each other during rotation of the cylinder-block and reaction rin about eccentric axes. With such a coupling, however, the pivotal axis of the arms remains fixed for-any particular adjustment of the eccentricity of the reaction ring with respect to the cylinder-block and moves automatically to a new position when the eccentricity of the parts is adjusted.

The cylinder-blocks of the pump and motor units are also provided with ports at one end which communicate with the radial cylinders and cooperate with the inlet and outlet ports in a valve-member in the casing. Each cylinderblock is provided with horizontal cylinders in its end opposite the ports which extend parallel to the axis of the block and communicate with the radial cylinders. Pistons in the horizontal cylinders are operated by the motive fluid in the radial cylinders and cooperate with a suitable abutment to hold the ported end of the cylinderblock engaged with the valve-member in the casing. With such a valving mechanism the horizontal cylinders can be so designed as to apply an axial thrust to the cylinder-blocks proportional to the pressure of the motive fluid but only slightly in excess of the force tending to separate the valving surfaces.

Fig. 1 of the drawings illustrates a hydraulic variable speed power transmission apparatus comprising an electric motor 2 having a multisectional casin 3 attached to its end-wall 4. The casing 3 comprises spaced annular sections and 6, an intermediate annular section 1, and a disk-like end-wall 8 which are held in assembled relationship by horizontal bolts 9 extending through the end-wall 8 and sections of the casing and screwed into the end-wall 4 of the electric motor 2. The motor 2 and easing 3 have feet H) for mounting the assembly, preferably on a tank ll constituting a reservoir for the hydraulic motive fluid. The intermediate section 1 of the casing 3 is in the form of a diaphragm or septum l5 which divides the casing into separate compartments I6 and H. The septum I5 is formed at its center with an annular hub constituting a valve-annulus l8 having an axial bore IS. The valve-annulus I8 is formed with arcuately-shaped cored valve-ports 22 and 23 extending axially therethrough, see Fig. 6, and its ends are finished to provide bearing-faces and 2|. The valveports 22 and 23 may function either as suction or exhaust ports depending upon the direction in which the apparatus is operated and either port is adapted to be supplied with motive fluid from the reservoir I I through a supply-line comprising a conduit 24 and a check-valve 25, see Figs. 1 and 3. Each check-valve 25 is adapted to close automatically when the motive fluid in its corresponding port 22 or 23 is under pressure and to open when suction exists to make up for any fluid leakage which may have occurred during operation of the apparatus.

A hydraulic pump 26 is mountedimthe compartment l6 and a hydraulic motor 21 is mounted in the compartment ll of the casing 3. The pump 26 comprises a composite shaft 28 journaled in an anti-friction bearing 29 in the bore I9 of the valve-annulus l8 and an anti-friction bearing 30 in the end-wall 4 of the electric motor 2. The shaft 28 has an enlarged annular boss 3| adjacent the bearing 30 providing a radial shoulder 32 and a cylindrical opening or chamber 33, see Figs. 1 and 4. A hollow stem or thimble 35 is attached to the end of the boss 3| on the shaft 28 by means of screws 36 inserted through its radial flange 34, the stem forming an extension of the shaft 28 and being'journaled in the antifriction bearing 30 surrounding the end of the motor-shaft 31. As shown in Fig. 1, the interior of the hollow stem or extension 35 of the shaft '28 is fluted for cooperation with the splines 38 on the motor-shaft 31 to connect the two shafts for rotation.

Mounted on the shaft 28 between the shoulder 32 and the valve-annulus l8 of the casing section I is a cylinder-block 42, see Fig. Lhaving a plurality of radial bores 43, see Fig. 2. The cylinderblock 42 is connected to the shaft 28 for rotation therewith by means of a key 44. A bronze valveplate 45, fixedly attached to the end of the cylinder-block 42 by brazing or other suitable means, is adapted to bear against the ported face 20 ing-section 1.

of the valve-annulus l8 n the intermediate cas- Extending through the valve-plate 45 and cylinder-block 42 are aeseries of ports 46, see Fig. 2, each of which is adapted to communicute with a cylinder-bore 43 and cooperate with. the ports 22 and 23 of the valve-annulus l8 as.

42 relative thereto. One of the .ports 22 and 23 in the valve-annulus I 8 will function as 'an'outle't from the plurality of cylinder-bores 43 while the other port functions as an inlet to the-cylinderborfes depending upon the direction in which the electric motor 2 rotates, the pump operating equally as well in either direction of rotation,

In the end-face of the cylinder-block 42 opposite from the valve-plate 45 are a series of horizontal bores-41 having axes extending at right angles to the axes of the radial cylinder-bores 43. Each horizontal bore 41 communicates with its corresponding radial cylinder-bores by means of-assmall port 43. A piston 49 is provided in each horizontal :bore for operation by the pressure of, the motive fluid acting through the-port- 46 leading from :the corresponding radial cylinder-bore 43. The pistons 49 bear against the radial shoulderr32 'onttheishaft'28 toapply a predetermined axial thrust to the cylinder-block 4-2 whichii sproporti'onal to and slightly in excess of the force applied by the pressure of the motive fluid tending to force the valve-plate -45 away from the fixed valve-annulus Won the casingsection I. v

Surrounding :the cylinder-block -42 is a reaction'ring 52 mounted to rotate in a carriage 53.

The :ring 52 is generally of annular form-and channel-shape in cross-section.- As herein shown the Ting 52 comprises three annular sections con- The carriage BIL-likewise is of-annular form,

see Fig. .2, and channel-shaped in cross-section toenclose the. ring in nested relationship. The

reaction :ring 52 .is :mounted to rotate on anti friction roller-bearings 58 .and 59 positioned between the carriage 'anduring at opposite sides thereof, .see Figs. 1 .and 4. The carriage 53 is mounted to slide vertically in'the casing-section Stoadjustthe eccentricity of the axis ofthe ring with respect to the axis of the'shaft-28. Forthis purpose the carriage i 53 :has flat vertical sides 6|] and-6| which slide on cooperating guide-members orways 62. and 63 on thejinterior of the casingsection 5,rseeFig. 2. Integral with or attachedto thGitOPJOf the carriage .53- -is :a screw-threaded stem 64 which projectsupwardly througha suitable opening in? the casing-section and through alined, :holes in spaced bearings 65 and '66 mounted-thereon. Positioned between the bearlugs 65 and '66 -is.a handwheel 61 having an'internally-threaded hub 68 whichcooperates with the threaded stem 64. By rotatin the handwheels the stem 64 maybe:movedaxially in-one' direction or the other which, in turn, will move the carriage 53 vertically with respect to-the casing-section 5 to adjust the eccentricity of the axis of the reaction ring 52 with respect to the axis of the shaft 28.

The hydraulic motor-unit 21 is of a construction substantially identical with that of the pump 26 but of opposite hand. For convenience of description the elements'of the motor are desig- 1 nated by different reference characters but similar details of construction are indicated by the same characters as used in the description of the pump. The motor-unit comprises a shaft 12- journaled in an anti-friction bearing 13 in the bore IQ of the valve-annulus l8 with an axial extension 1| journaled in a ball-bearing 14 in the end-wall 8 of the casing 3. The shaft 12 has a boss 3| forming a shoulder 32 anda cylindrical chamber 33 at its end. The shaft-extension II has a radial flange fastened to the end of the boss 3| 0n the shaft 12 by screws 35 with-its end projecting outwardly through the end-wall 8 of the casing 3 for connection with the apparatus to be driven. Mounted on the shaft l2 is a cylinder-block 18 having radial cylinder-bores 43 and horizontal bores 41 identical with those described with respectto the pump 26. The cylinder-block 18 is connected to the shaft 12 by means of a key '44 and'the radial bores 43 are connected to the horizontal bores by means of ports 48. At its inner end the cylinder-block 18 has a valve-plate '45 brazed thereto and adapted to bear against the ported face 2| of the valveannulus |8 on the casing-section 6. The cylinder-block" and'valve-plate 45 also are provided with a series of laterally-extending ports 45, one for each cylinder-bore 43, arranged to cooperate with the ports 22 and 23 in the valve-annulus I8 in the manner previously described with respect to the pump.

Surrounding the cylinder-block i8 is a ring 89 mounted to rotate in a carriage 8|. The ring 8| and carriage 8| are of a construction identical with that of the ring 52 and carriage 53 of the pump, being of channel-shape in cross-section and nested one within the other. The ring 80 is rotatable in roller-bearings 58 and 59 positioned between the ring and carriage at opposite sides thereof with annular guide-p1ates55 and alaterhandwheel 61 having its hub 68 in threaded enconstitute linings for the cylinders.

gagement with the screw-threads on a stem 64 extending'from the carriage and cooperating with spaced bearings 65 and '66.

Mounted ineach bore 43 of the cylinder blocks 42 and 18 of the pump andmotor units Hand 2-! is a flanged sleeve which is fastened in place by brazing or welding it thereto, see Fig. 31. The-- sleeves 85 are of hardened steel or the like and A piston. 86 mounted to reciprocate in each cylinder 43 has a close fit within the'bore 0f theliningsleeve 85.

In accordance with the present invention the piston-rod foreach piston 86' is adapted to rock on the reaction ring 52 or 80 during rotationof the cylinder-block 42 or T8 and ring 52 or 130 about eccentric axes. Each piston-rod 8?! has a ball-joint at one-end for connecting it to the pis ton and a rocker-bearing .89 et .its opposite :end

provided with a-curved face :90 'iforicontact with theinterior of the ring 52 or tangentially thereof, see Fig. 2. An integral spherical enlargement or ball 88 at the end of each piston-rod 87' is adapted to seat in a correspondingly-shaped semispherical socket 9| in its piston 86, being held in place by means of a ring 92 having a spherical cavity overlying a portion of the ball. The ring 92 is clamped in position on the piston 86 by means of a second ring 93 screwed into the skirt of the piston, see Fig. 7.,

The curved face 90 of the rocker-bearing 89 at the outer end ofeach piston-rod 81 and the cooperating face on the interior of the reaction ring 52 or 80 may have any suitable contounto give the desired piston-stroke and pressure characteristics to the motive fluid. In the preferred form of construction illustratedin Figs. 1, 2, and? of the present drawings, the curved face 90 of each rocker-bearing 89 is of arcuate contour concentric to the pivotal axis of the piston-rod 8'1 at the center of the ball 88 and the reaction ring 52 or 80 has a fiat contact face 94 normal to a radius of the ring and disposed opposite each cylinder 43. With such a construction and arrangement of the piston-rods 81 and reaction ring 52 or 80 the arcuate faces 90 of the rocker-bearings 89 will engage the flat faces 94 on the ring tangentially and the point of contact of each rocker-bearing will always aline with the axis of its cylinder in any angular position of the piston-rod, see the center line A-O in Fig. 2. In other Words, the line of force from the pivotal axis of the pistonrod 81 to the point of tangential contact of the arcuate face 90 of each rocker-bearing 89 with the flat face 94 on the ring 52 or 80 will always coincide with a radius from the center of the cylinder block 42 or I8.

To retain the piston-rods 81 in proper position while the pump and motor units and 2! are idle the rocker-bearings 89 are provided with laterally-projecting pins 96 which engage in arcuate slots 91 in th sides of the annular guide-plates 55, previously referred to, at opposite sides of the rings 52 and 80. The slots 9'! are of such shape as to hold the arcuate faces 90 of the rocker-bearings 89 in contacting engagement with the flat faces 94 of the rings 52 and 80 while permitting angular movement of the piston-rods 0'! to the various positions illustrated in Fig. 2.

Fig. 3 shows a form of construction of the invention identical with that of Figs. 1 and 2 except as to the form of the contact faces on the ring 98 which are engaged by the arcuate peripheries 90 of the rocker-bearings 89. In this embodiment of the invention illustrated in Fig. 3 the interior of the ring 98 is of cylindrical contour while the arcuate periphery 90 of each rocker-bearing 89 is concentric with the pivotal axis of its piston-rod 81. With this form of construction the line of force fromthe pivotal axis of the piston-rod 81 to the point of tangential contact of the rocker-bearing 89 on the ring 98 will always coincide with a radius from the axis of the ring as shown by the line B-Y in Fig. 3. It will be obvious, therefore, that with the form of construction illustrated in Fig. 3 a side thrust on the pistons 86 is engendered, resulting in increased wear over that which will result from the use of the improved construction illustrated in Fig. 2. It is to be understood, however, that other modified forms of contact surfaces may be provided on the rocker-bearing 89 of the piston-rods 81 and ring 52 or 80 to give any desired characteristics. For example, the contact faces may be so formed as to give a constant flow-characteristic to the motive flu1d whereby to avoid impulses caused by the usual harmonic motion of the piston.

The present invention also eontemplates'the' use of couplings of novel construction for connecting the shaft 20 of the pump 26 and the shaft 12 of the motor 21 to their respective reaction rings 52 and 80. Each of the couplings comprises a plurality of radial rods or arms IOI, I02 and I03, see Figs. 1 and 4, pivotally-connected at their inner ends and having articulated sliding connections with the boss 3I an'd annulus or colar 56 of the shaft 28 or 12 and ring 52 or 80. As illustrated in Fig. 4, the arm- I0,I has a bearing-block I04 at its inner end while the other two arms I02 and I03 have'bifurcated ends or forks I05 and I06, the fork I05 straddling the block I04 and the fork I06 straddling the end I05. The inner ends of the arms IOI, I02 and I03 are located in the cylindrical chamber 33 in the shaft 28 or 12 and pivotally connected by a single pin I01 extend ing through the bifurcated ends I05 and I06 and the bearing-block I04. a

To provide for an articulated sliding connection of the arms IOI, I02 and I03 with the shafts- 28 and I2 and rings 52 and -the bosses 3| of the shafts are each provided with a plurality of bores I 09 in which pins III are journaled for rocking movement and the collars 56 of the rings are each provided with a plurality of bores II 0 in which similar pins I I2 are journaled. The pins III and H2 are provided with transverse holes through which the arms IOI, I02 and I 03 extend and the sides of the bores I 09 and H0 are beveled to provide clearance to allow the arms to rock about the axes of the pins. Al-' though the couplings are shown in Fig. 4 of the drawings as comprising three arms IOI, I02 and I03 with the pins III and H2. arranged apart around the boss 3| and collar 56, it is to be understood that the couplings may have a greater number of arms if desired. During rotation of the shaft 28 or 12 its motion is transmitted by the arms IOI, I02 and I03 of the coupling to rotate the ring 52 or 80, the arms being caused to rock or swing relative to each other during this rotation with the pins III and H2 rocking to permit this relative movement of the arms. a

The construction and arrangement of the present improved couplings eliminates the vibration that is present in the usual type of coupling employed to connect parts for rotation about eccentric axes. The elimination of 'vibration is due to the fact that the axisoflthe pivotpin I01 of each coupling remains stationary during rotation of the coupling at any particular adjustment of the eccentricity of the reaction ring 52 M80 with respect to the shaft 28 or12. However, when the eccentricity of the reaction ring 52 or 80 is adjusted with respect-to'the axis of the shaft 28 or I2 the axis ofthe pivotpin I01 will be moved in the opposite direction from that of the axis of the shaft-as indicated diagrammatically in Fig. 5. In Fig. 5 the fullllnes indicate the relationship of the arms I 0I, I02 and I03 of the coupling for a certain acljustmentof the eccentricity of the reaction" ring 52.01180 with respect to theshaft 28 or I2. 'It will be noted that the axis X of the pivot-pin- I01 is located below the-axis O. of the shaft 28- or 12 a distance equal to the eccentricity of the axis Y of the'ring 52 or 80 above the'axis. of the shaft. Also in Fig. 5, the dash-lines indicate the relationship of they arms IOI, I02 and M3 and position of the ring 52 or 80 ata point when'the axis Y" of the ring is. adjusted towardtheaxis O ofthe shaft. 28'. or T2 to the position indicated by the reference character Y". When the reaction ring 52 or is adjusted in the mannerlastdescribed. the axis X" of] the pivot-pin. IOl will. be shiftediautomatically toward the axis. O of the shaft 28 or 12 to the position indicated bythe reference character X It: will; be noted; that the; positions. inicated at X and Y." are always equi-distant from the axis of'the shaftzfl' or I2 but; at opposite sides thereof. Atter the. eccentricity has been once adjusted, however; the axis X of the pin the compartments W and I1 fof the casing 3.

Beside providing forjthedrainage of escaping motive fluid the passages I and HI; provide for circulating the motive fluid, preferably oil, to lubricate the pivot-pins J01, arms I'Ulj, H12

and I 03 and rockingpins Hi and H2. oflthe A couplings. Theheads oft-he pistons 8.6" also are provided with-axial passages l2'2, see; Fig, 7, for supplying motive fluid to lubricate the balls 88 on the piston-rods 8'1 as-they rockinthe sockets at in thepi'stons. One embodiment: of the inventionhaving been described in detail the mode of operation of the apparatusis explained as follows:

For the' purpose" of thepresent description let itbeassumed that the cylinders "and connect.- ing passagesin the pump 26* and hydraulic motor 2-11 are-filled with motive fluid and that the electric motor Zis energized t'o turnin clockwise direction aslviewed in Fig. 2. Rotation of the motor shaft 3:": thuswill rotate'the-shaft 28 and'cylindereblock 42 of. the pump hr the same direction. The i rotation ol' the shafit' 25*wil1 be transmitted to. the reaction rihg'i! thea'rms I'M, i 02 and 103 which are slid'ably connected to the rockable pins HI and M2 in the boss 3 of the shaft and the collar 56 of the r-mg, Fig. QQso'tHat the shaft and' ring. will rotate at thesame angular velocity; During. this rotations! the cylinder block "and reactionxring 52 about eccentricaxesthe arms IO'l, H12 and. til-t of the coupling will rock with respect to? each other" and slide axially in the pins H I and'l l Z-irrthe hub il of theshazftlli'and the collan56' of'themm; K2. The oppositely-inclined bevels at the sides-oi the openings "15 in the boss 3| and theopenings I'IO in the collar 56, in which the pins. Mal and IiI Zare journaledgwill permit the, arms. to rock singularly and the transverse holes: in the pins. will. permit the arms to slide axially; 1 i

Due tothe eccentricity of the axis of the ring 52 with respect to the" axis ofthe shaft 28 the distance'between" the periphery of the" cylinderblock and the interior face-of the reaction ring will increase progressively on one side of the pump. from. minimum to maximum while the distance betweenthe periphery of the cylinder-block. and

the interior face of the ring at the oppositev side of the pump will decrease gradually" from maximum to minimum. The pistons 88 in the cylin,- ders 43 thus will be moved successively through. a suction stroke during one-half of a revolution to draw motivefiiiid. into the cylinders through the intake port, Zlvinthevalve-annulus l8. and the ports, i nzthe-oyli'nder block 42. During the seccnd hal-f-reyolutionthe; pistons willbe moved inwardly in the-cylinders 4.3 successively to deliver the .motive. fluid under pressure throughthe ports 46 in the cylinder-block.42 and. the'port 2=3 inthe valve annulus I8; .In other words, the pistons 86 he'movedithroiigh a suction stroke at the. leftvhandside.o1;',the pump as viewedin-Fig; 2-, and moved through. a pumping stroke at the, righthand. sideoi 'thepump. By reference taEig. -6 it willhe/notedthat the ports 46 inthercylinder mats. 42" tor; three of; the. cylinders 431 are: alined with the. intake port 22. .in' the valve-plate l-B ,While three: other-ports 46 are alined with. the exhaust port 23, a seventhport being positioned betweentheinta-ke andexhaustports a Yr i Corresponding. points on; the shaftx28 and ring 52 will; coincide with a vertical. line through the axesO and Y oi the shaft anderingbelow the shaft, seeliglifi... During rotation of, the shaft 28 and; ring 52 at the same. angular velocity througha quarter revolutionthe point on the ring 25 is gradiially displaced. ventically inadvance of the correspondingpoint on. the shaft due to. the; eccentricit'y of. the. axes O andY otthe. shaftand ring. At the end of.a.quart.er-revolution thedis-f placement.- of the corresponding points on the shaft 28 and. ringil will be equalto the eccentricity of the axes C). and Y of. theshaft. andring. During the second. quarterrevolution the. (118';- placement of the corresponding points. on the shaft 28" and. ring. 52. will diminish'gradua'lly. until the points a'gain coincidenwith a vertical, line through. the axes. Q and Y. i During the. third displaced. in advance: 0t thecorresponding point on! the ring 5,2..until. the displacement, reaches a maximum corresponding to the. eccentricityof the axes. O and During. the: fourth quarterrevolution the. displacement gradually diminishes until the corresponding points on the shaft-28: and ring- 52. again coincidewith the: vertical lines: ,Due to the gradually increasing and diminishing dis placement: between; thev ring 52: and cylinder-block 42 during their rotation at the same angular velocity: a relative movement will take place be tween the contact faces of the piston -rods" 81 and the-interior of the-ring 52? Td compensate for such: relative movement of. the shaft 28; and ring 52 the arcuate peripheries SW01- the rocker bearingslw at the ends of the piston-rods*8-'l 'wil1 rock on the flat faces on the interior of-the ring 52:: 1

Furthermore, due to the arcuate contour of the roclze'rb earings 89 011 the piston -ro'ds, 81' they will contact the flatfacs 941311 the em; 52'tangentiallyand the point 'of tangential'contact of each piston-rod invariably 'wi ll aline with the axis of its related cylinder" 43"i'n 'anyangular posig tion oi the piston-rod; note (the direction of force indicated by the line Ag-O inFig. 2 Ass; result, the force for moving the pistons. 86' in the ,cyli'n-. ders 43' always, will be applied in linewith' the axis of the cylinders to prevent crampingof the. pistons; and further to. reduce the wear: on the. piston and cylinders to a minimum. The. arcuate. races ll'ofthe rocker-bearings 89 on thepiston rods 81' invariably will bef naintainedin contact with theflat faces St on the ring. 5.2.by the: en,

gagement of the laterally projecting pinsfiliin the slots 91 in the guide platesji, .Tliecurved slots 9'! are ofa contoun'however, such as to permit rocking movement of the piston-rods 81 to the various angular positions shown in Fig. 2.

The motive fluid under pressure in the cylinders 43 at one sideof the pump 26 will be caused to flow through the small ports 48 into the horizontal cylinder-bores 41 to operate the pistons 49. Consequently the pistons 49 will be forced against the radial shoulder 32 on the boss 3| of the shaft 28 to apply a predetermined axial thrust proportional to and slightly in excess of the force produced by the motive fluid tending to separate the valve-plate 45 from theflxed valve-annulus I8. As a result, the valveplate 45 of the cylinderblock will be maintained in firm engagement with the valve-annulus I8, but with a force onlyslightly in excess of that required to preventleakage whereby to maintain the friction between the moving parts at a minimum. b p

The motive fluid delivered under pressure from the pump 26 is conducted through the port 23 in the fixed valve-annulus I8 and the ports 46 in the cylinder-block I8 at the right hand side of the hydraulic motor-unit 21, as viewed in Fig. 2, and into the cylinders 43 thereof. The introduction of the motive fluid into the cylinders 43 of the motor 21 willapply pressure to' thepistons 86 to transmit force through the piston-rods 81 to the reaction ring 88. Due to the eccentricity of the axis of the cylinder-block. I8 and ring 80 a force-couple is produced which will cause rotatlon of the ring 80 in counterclockwise direction. The connection of the hub 3| of the shaft I2 with the collar56 of the ring 80 b means of the arms I DI, I02 and I03 of the coupling will cause the shaft I2 andcylinder-block 81 keyed thereto to rotate in unison with the ring v80, At the opposite or lefthand side of the hydraulic motor 21 the ports 46 communicate with the port 22 in the valve-annulus I8 tofexhaust the motive fluid from the cylinders 43 to cause it to flow back to the pump 26. I

During the rotation of the shaft I2 and the reaction ring 80 the rocker-bearings 89 on the piston-rods 81 will rock on 'theringin the manner previously explained with respect to the pump i 26. The motive fluid in the cy1inders'43 of the cylinder-block I8 will be transmitted through the small ports 48 to operate the pistons 49 which bear against the annular shoulder 32 on the boss 3| of the shaft 'I2'to'apply a predetermined axial I thrust to the cylinder-block 18 to maintain the valve-plate 45 engaged with the face 2I of the fixed valve-member I8. As in the case of the pump 26, the valve-plate 45 of the cylinder-block I8 of the motor 21 is held in engagement with the face 2| of the fixed valve-annulus I8 with'a force proportional to the pressure of the motive fluid, but only slightly in excess of that required to hold the valve-members engaged; I

The variable-speed power-transmission apparatus will continue to operate in the manner indicated, the pump 26 supplying motive fluid under pressure to the hydraulic motor 21 and the ports 46 in both of the cylinder-blocks 42 and I8 cooperating successively with the ports 22 and 23 and the fixed valve-annulus I 8. The motive fluid exhausting from the motor 21. will flow through the port 22 which constitutes the intake for the pump 26. Any motive fluid escaping from the system due to leakage between the pistons and cylinders will be compensated for by the flow from the tank I I through the check-valve '25 and conduit 24 connected to theport 22 in the valveannulus I8;

The relative speeds of the pump and motor cylinder-block 42.

block 18 of the hydraulic motor 21. is'greater than the volumetricdisplacement of the cylinders 43 in the. cylinder-block 42 ofthe pump 26, then the motor 21 willrotate ata slower rate of. speed than that of the pump 26..v On the other hand, if the volumetric displacement of the cylinders 43 of the hydraulic motor 21 is less than the volumetric displacement-of the ,cylinder 43 of the pump 25 then the motor will rotate at a highverrateo f speed than .thatof the pump. Usually, the volumetric displacement of the pump is regula'ted for a particular condition by adjusting the eccentricity ofthe ring 52 with respect to the v For this purpose the handwheel 61 may, be rotated to slide the threaded ,stem64 axially. and -move the carriage 53 vertically. The axis of. the reaction ring 52 rotatably mounted on the carriage 53 thus can be adjusted with respect to the axis of the shaft 28. With the eccentricity. of thepump 26 adjusted fora particular condition the eccentricity of thereaction ring o'f thehydraulic motor 21 may be adjusted with respect to. its cylinder-block I8 to produce any desired variation in the speed of the motor within certainprescribed limits.

It will now be observed from-theforegomg specification that the present invention provides a hydraulic variably-speed power-transmission apparatus having pump andmotor units with piston-rods adaptedtorock on the reaction rings to reduce friction and wear.; It also will be observed thatthe invention provides a novel form of coupling for connecting the cylinders and'reaction ring of the pump or motor unit for rotationat the same angular velocity about eccentric axes. It will be observed still further that the present invention provides a novelform-of valving mechanism in which the valve-surfaces are held, in engagement with a predetermined'axial force proportional to the pressure of the motor fluid but only slightl in excess of that required to. maintain the valve surfaces engaged. ,While a preferred form nf-apparatus incorporating .the novel features of thejpresent inventionand asingle variation in the form of the contact surfaces on the piston-rods and reaction ring are .herein shown and described by way of illustration, it 'is to be understood that other modifications-may be made-in the form of the contact faces on the piston-rod and reaction ring and in..the construction and arrangement of the parts of the-apparatus without departing from the. spirit or scope of ,the invention. Therefore, without. limiting myself in this respect, I claim:

. 1,-In, a pump or motor unit, a rotor compris ing radial cylinders'arranged in angular relationship and-mounted for rotation about a fixed axis, pistonsin said-cylinders, a ring surrounding the cylinders With its axis eccentric to the'axis of rotation of the cylinders, means for connectin the ring for rotation with the 'cylinders, and a piston-rodfor each piston having oneend pivotally connectedto its {fist/0115311612 curved rocker-bearing at its opposite endengaging the ring tangentiallyon a single line of .contact and rockable thereon without substantial sliding-movementl, 1.

2 In a pump or. motor unit, a shaft, a rotoron said shaft comprising radial cylinders arranged in, angularspaoed relationship for rotation about the axis of .theshaft, pistonsin said aaeigzzei 7 cylinders, a ring surrounding: the. cylinders. with its. axis eccentric to the. axislof the shaft, means for connecting the ring. for rotation with the cylinders, and a piston-rod for each piston having one end; pivotally. connected to= its pistonand a curved rocker-bearing at itsoppflsite end engaging the ring tangentially on. a, single line 'of contact, said rocker-bearing being curved in. an arc concentric tothe pivotal. axis. of thepistonrod to adapt it. to the rock on thering without substantial, sliding movement.

3. In a pump. or motor unit, ashaflt, a rotor on said. shaftcomp-rising radial cylinders arranged in angulanrelat-ionshlp for rotation. about the axis of the shaft, pistons in said: cylinders. a ring surrounding the cylinders with. it axis eccentric to the axis of the shaft, means. for connecting the ring. for rotation with the; cylinders, means forzrelatively shifting the ring and rotor to adjust the eccentricity of the. axes of rotation,, and a piston-rod for each pistonhaying one end pivotally connected to its piston and a curved: rocker-bearing at its. opposite endengaging. the; ring tangentially on a single line of. contact, said rocker-bearing. being adapted to reckon the e ring without substantial sliding. movement .to-

compensate for the; relative movement of'the cylinder and ring. during their rotation. abouteccentric axes.

- 4. In a pump-or motor unit, a shaft, a rotor on onthe ring without substantial. sliding movement to compensatefor therelat-ive movement of the cylinder and ring: during their rotatiomjabout eccentric axes;

5. Ina pump or'motor'uni-t, a shaft, a rotor on said shaft comprising radial cylinders, arranged in angular relationship for rotation aboutthc axis of the shaft, pistons. in said cylinders. a ring surrounding the cylinders with: its axis eccentric tothe axis of the shaftmeans forconnecting the ring for rotation: with. the cylinders, a. piston-- rod for each piston havingaone end pi otally connected tor its piston and a curved rocker-bearing at its opposite end engaging the ring tangentially on a single line of contact and; rockable thereon. without substantial sliding movement to compensate for the. relative movement of the cylinder and: ringduring their rotationabout eccentric axes, and means for connecting, the

onthe ring tangentially on a single: line of contact,. each. rocker-bearing being adapted to rock on one of. the flat facesof the ring withoutsubstantial sliding movement to compensate for the 'relative movement/of the cylinder and ring durders, means for connecting. the ring for rotarocker-bearing of each piston-rod to the ring. to

tion with. thecylinders, saidring having a flat interior face opposite. each cylinder,. and a pistonrod for. each pistonl having one end pivotally connectedto itspistonand a curved rocker-bearing at its: opposite end. engaging one of the fiat faceson the ring. tangentially on. a single line of contact and: rockablethereon without substantial sliding movement, each rocker-bearing hav ing its. face curved in an arcconcentric to the pivotal axis of its piston-rod: whereby to cause said rocker-bearing to engage the flat face on the ring in a plane coincident. with the axis of] the cylinder at any angular position of the" piston;- rod.

8.. In a pump or motor unit, a shaft, radial cylinders arranged: in. angular spacedi relationship for rotation: aboutthe axis of the shaft, pistons in said cylinders, a' ring surrounding thecylinders-with its. axis eccentric to the axisof rotation of the cylinders, means for'connecting the ring for rotation with the cylinders, said ring having a flat face opposite each: cylinder, at piston-rod for eaclr piston having one end pivotally connected to its piston and a curved rocker-bearing at its" opposite end engageable with cheer the flat faces on the ring and rockable thereon to compensate for the" relative movement of the cylinder and ring during their rotation about eccentric axes, said rocker-bearing having an arcuate face curved in an arc concentric to: the pivotal axis of the piston-rod whereby to cause the rocker-bearing to engage the flat face on the ring in: a planev coincident with the axis of the cylinder in any angular position of the piston-rod,. and means for maintaining. the arch;- ate face of each rocker-bearing. in. engagement with the ring whi-lepermitting its rocking movement; relative thereto.

9. In a pump or motorunit, a; rotorcomprising radial cylinders arranged in angular relationship for rotation about a. common axis, pistons in said cylinders, a ring surrounding the cylinders with its axis eccentric to the axis of rotation of the cylinders, a piston-rod for each piston extending betweenits piston and. the ring, and a. coupling having a plurality of radial arms for connecting the ring. for rotation with therotor, said arms of the coupling being: pivotally connected to, each other-at their inner ends on a common axis and having articulated connections with the rotor and rmg.

10. In a pump or motor unit, a rotor compris ing radial cylinders arranged: in: angular relationship for rotation about. a; common axis, pistons in said cylinders, a ring: surrounding the cylinders with its axis eccentric to' the axis of rotation thereof, means for relatively shifting the ringand rotor to adiiust the eccentricityof. their axes of rotation, a piston-rod for each piston extending between its piston and the ring, anda coupling. havinga plurality of. radial arms for connecting the.- ring for rotation with the. rotor andpermitting adjustment of their axes, said; radial arms of the coupling being pivotally connected to each other at their inner ends on a common axes and having articulated connections with the rotor and ring.

11. In a pump or motor unit, a shaft having a hollow boss forming a rim, pins mounted in the rim to rock on axes parallel to the axis of the shaft, a rotor comprising radial cylinders arranged in angular relationship on said shaft for rotation therewith, pistons in said cylinders, a ring surrounding said cylinders with its axis eccentric to the axis of the shaft, pins mounted in the ring to rock on axes'parallel to the axis of the ring, said pins on the shaft and ring being spaced in the same angular relationship, a pistonrod for each piston extending between its piston and the ring, and a coupling having a plurality of arms extending outwardly through the rockable pins in the shaft and ring to connect the latter for rotation as a unit, the inner ends of said arms being pivotally connected to each other on a common axis to permit relative swinging movement thereof.

12. In a pump or motor unit, a casing having a fixed valve-element with inlet and outlet ports, a cylinder-block mounted to rotate and slideaxially in the casing and having radial cylinders therein for receiving motive fluid, said cylinderblock having an end-face in a plane parallel to the axes of the cylinders for engagement with. the valve-element in the casing, said end-face of the cylinder-block having ports communicating with the cylinders and adapted to cooperate with the inlet and outlet ports in the valve-element, a ring surrounding the cylinders, pistons in the cylinders, piston-rods extending between the pistons and ring, and expansible means operated by the pressure of the motive fluid in the cylinders for applying an axial force to the cylinder-block to maintain its end-face engaged with the valve-element of the casing.

13. In a pump or motor unit, a casing having a fixed valve-element with inlet and outlet ports, a cylinder-block mounted to rotate and slide axially,in the casing and having radial cylinders for receiving motive fluid, said cylinder-block having an end-face for engagement with the valve-element and having ports communicating with the cylinders adapted to cooperate with the inlet and outlet ports of the valve-element, the opposite end of the cylinder-block having axial cylinders communicating with the radial cylinders, a ring surrounding the radial cylinders, pistons in the radial cylinders, piston-rods extending between the pistons and ring, and pistons in the axial cylinders in the end of the cylinderblock arranged to be operated by the motive fluid in the radial cylinders for applying an axial force to the cylinder-block to maintain its end-face engaged with the valve-element of the casing. v

14. In a pump or motor unit, a casing having a fixed valve-element with inlet and outlet ports, a shaft mounted to rotate in the casing and having a radial abutment thereon, a cylinder-block keyed to the shaft and slidableaxially thereon, said cylinder-block having radial cylinders for receiving motive fluid and axial cylinders in one end thereof communicating with the radial cylinders, the opposite end-face of the cylinder-block being engageable with the fixed valve-element and having ports communicating with the radial cylinders adapted to cooperate with the inlet and outlet ports in the valve-element, a ring surrounding the radial cylinders, pistons in the radial cylinders, piston-rods extending between a fixed valve-element with inlet and outlet ports,

a shaft mounted to rotate in the casing and having a radial abutment thereon, a cylinder-block keyed to the shaft and slidable axially thereof, said cylinder-block having radial cylinders for receiving motive fluid and axial cylinders at one end thereof communicating with the radial cylinders, the opposite end-face of the cylinder-block being engageable with the fixed valve-element and having portscommunicating with the radial cylinders adapted to cooperate with the inlet and outlet ports in the valve-element, a ring surrounding the radial cylinders, pistons in the radial cylinders, a piston-rod for each piston having one end pivotally connected to its piston and a curved rocker-bearing at its opposite end engageable with the ring tangentially thereof, radial arms pivotally connected at'their inner ends and having articulated connections with the shaft and ring, and pistons in the axial cylinders in the cylinder-block engageable with the radial abutment on the shaft, said piston in the axial cylinders being operated by the motive fluid in the radial cylinders for applying an axial thrust to the cylinder-block to hold its end-face engaged with the valve-element of the frame.

16. In a device of the typ indicated, a casing having a central valve-element, said valve-element having arcuate inlet and outlet ports extending therethrough, a pump unit in the casing located at one side of the valve-element and having a cylinder-block mounted for rotation and axial sliding movement, a motor unit mounted in the casing at the opposite side of the valveelement from the pump unit and having a cylinder-block mounted for rotation and axial sliding movement, said cylinder-blocks of the pump and motor units each having radial cylinders and axial cylinders communicating with the radial cylinders, the adjacent end-faces of the cylinderblocks being engageable with the opposite sides of the fixed valve-element and having ports communicating with the radial cylinders, said ports being adapted to cooperate with the inlet and outlet ports in the valve-plate, rings surrounding the cylinder-blocks, pistons in the radial cylinders, piston-rods extending between the pistons and rings, and pistons in the axial cylinders in the cylinder-blocks, said pistons in the axial cylinders of the cylinder-blocks being operated by the motive fluid in the radial cylinders and cooperating with abutments for applying axial forces on the cylinder-blocks to hold their adjacent endfaces engaged with the opposite sides of the valve-element.

17. In a pump or motor unit, a rotor comprising radial cylinders arranged in angular relationship for rotation about a fixed axis, pistons in said cylinders, a ring surrounding the cylinders with its axis eccentric to the axis of the rotor, means for connecting the ring for rotation with the cylinders, a piston-rod for each piston having one end pivotally connected to its piston .and a curved rocker-bearing at its opposite end engaging the ring tangentially on a single line of contact and rockable thereon without substantial sliding for rotation with the cylinders, a piston-rod for eachpiston having one end pivotally connected to its piston and a curved rocker-bearing at its opposite end engaging the ring tangentially on a single line of contact and rockable thereon without substantial sliding movement, said ring provided with slots, and pins on the rocker-bearings of the piston-rods engaging the slots in the ring toprevent disengagement of said bearings from the ring while permitting them to rock relatively 10 of the ring.

CHRISTIAN E. GROSSER. 

